| 1 | //go:build unix |
| 2 | |
| 3 | package host |
| 4 | |
| 5 | import ( |
| 6 | "bytes" |
| 7 | "errors" |
| 8 | "go/ast" |
| 9 | "go/parser" |
| 10 | "go/token" |
| 11 | "os" |
| 12 | "os/user" |
| 13 | "path/filepath" |
| 14 | "strings" |
| 15 | "testing" |
| 16 | ) |
| 17 | |
| 18 | func TestRootRegistryRefusesPlantedFilesBeforeSQLite(t *testing.T) { |
| 19 | u, err := user.Current() |
| 20 | if err != nil { |
| 21 | t.Fatal(err) |
| 22 | } |
| 23 | if u.Uid == "0" { |
| 24 | t.Skip("this test simulates root repair with the current non-root service identity; real root credentials have separate coverage") |
| 25 | } |
| 26 | for _, name := range []string{"symlink", "dangling-symlink", "hardlink-wal", "hardlink-shm", "symlink-parent"} { |
| 27 | t.Run(name, func(t *testing.T) { |
| 28 | dir := t.TempDir() |
| 29 | victim := filepath.Join(dir, "victim") |
| 30 | data := filepath.Join(dir, "data") |
| 31 | if err := os.Mkdir(data, 0700); err != nil { |
| 32 | t.Fatal(err) |
| 33 | } |
| 34 | path := filepath.Join(data, "registry.db") |
| 35 | if name != "dangling-symlink" { |
| 36 | if err := os.WriteFile(victim, nil, 0640); err != nil { |
| 37 | t.Fatal(err) |
| 38 | } |
| 39 | } |
| 40 | switch name { |
| 41 | case "symlink", "dangling-symlink": |
| 42 | err = os.Symlink(victim, path) |
| 43 | case "hardlink-wal": |
| 44 | err = os.Link(victim, path+"-wal") |
| 45 | case "hardlink-shm": |
| 46 | err = os.Link(victim, path+"-shm") |
| 47 | case "symlink-parent": |
| 48 | alias := filepath.Join(dir, "alias") |
| 49 | err = os.Symlink(data, alias) |
| 50 | path = filepath.Join(alias, "registry.db") |
| 51 | } |
| 52 | if err != nil { |
| 53 | t.Fatal(err) |
| 54 | } |
| 55 | before, beforeErr := os.Stat(victim) |
| 56 | logged := captureLog(t) |
| 57 | reg, openErr := openRegistryConverging(0, u.Username, path) |
| 58 | if reg != nil { |
| 59 | reg.Close() |
| 60 | t.Fatal("unsafe registry reached SQLite") |
| 61 | } |
| 62 | if openErr == nil { |
| 63 | t.Fatal("unsafe registry accepted") |
| 64 | } |
| 65 | if !strings.Contains(strings.ToLower(logged()), "alert") { |
| 66 | t.Errorf("refused file had no alert: %s", logged()) |
| 67 | } |
| 68 | after, afterErr := os.Stat(victim) |
| 69 | if errors.Is(beforeErr, os.ErrNotExist) { |
| 70 | if !errors.Is(afterErr, os.ErrNotExist) { |
| 71 | t.Fatalf("dangling link target created: %v", afterErr) |
| 72 | } |
| 73 | } else { |
| 74 | if afterErr != nil { |
| 75 | t.Fatal(afterErr) |
| 76 | } |
| 77 | beforeUID, beforeGID, _ := fileOwner(before) |
| 78 | afterUID, afterGID, _ := fileOwner(after) |
| 79 | if beforeUID != afterUID || beforeGID != afterGID || before.Mode() != after.Mode() || before.ModTime() != after.ModTime() { |
| 80 | t.Fatal("victim ownership, mode or modification time changed") |
| 81 | } |
| 82 | contents, err := os.ReadFile(victim) |
| 83 | if err != nil || !bytes.Equal(contents, []byte{}) { |
| 84 | t.Fatalf("victim changed: %q, %v", contents, err) |
| 85 | } |
| 86 | } |
| 87 | for _, suffix := range []string{"-wal", "-shm", "-journal"} { |
| 88 | if _, err := os.Lstat(victim + suffix); !errors.Is(err, os.ErrNotExist) { |
| 89 | t.Fatalf("SQLite created victim sidecar %s: %v", suffix, err) |
| 90 | } |
| 91 | } |
| 92 | }) |
| 93 | } |
| 94 | } |
| 95 | |
| 96 | func TestPrivilegedRegistryEntryPointsUseServiceBoundary(t *testing.T) { |
| 97 | for _, tc := range []struct{ file, function, opener string }{ |
| 98 | {"agent.go", "runAdoptWithEnsureSystemUnits", "withClaimRootRelease"}, |
| 99 | {"agent.go", "runAdoptUnderRootRelease", "openServiceRegistry"}, |
| 100 | {"systemapply.go", "openSystemRegistry", "openServiceRegistry"}, |
| 101 | {"claimstop_run.go", "RunInstanceControl", "openServiceRegistry"}, |
| 102 | {"claimstop_run.go", "instanceRegistryHostApp", "openServiceRegistryReadOnly"}, |
| 103 | {"rootgeneration_rows.go", "productionGenerationRegistryInventory", "openServiceRegistryReadOnly"}, |
| 104 | {"claimjournal_migration.go", "RunSystemJournalMigrate", "openServiceRegistry"}, |
| 105 | } { |
| 106 | t.Run(tc.function, func(t *testing.T) { |
| 107 | f, err := parser.ParseFile(token.NewFileSet(), tc.file, nil, 0) |
| 108 | if err != nil { |
| 109 | t.Fatal(err) |
| 110 | } |
| 111 | found := false |
| 112 | for _, decl := range f.Decls { |
| 113 | fn, ok := decl.(*ast.FuncDecl) |
| 114 | if !ok || fn.Name.Name != tc.function { |
| 115 | continue |
| 116 | } |
| 117 | ast.Inspect(fn.Body, func(n ast.Node) bool { |
| 118 | call, ok := n.(*ast.CallExpr) |
| 119 | if !ok { |
| 120 | return true |
| 121 | } |
| 122 | if id, ok := call.Fun.(*ast.Ident); ok && id.Name == tc.opener { |
| 123 | found = true |
| 124 | } |
| 125 | if sel, ok := call.Fun.(*ast.SelectorExpr); ok && (sel.Sel.Name == "Open" || sel.Sel.Name == "OpenReadOnly") { |
| 126 | if id, ok := sel.X.(*ast.Ident); ok && id.Name == "registry" { |
| 127 | t.Error("privileged caller directly opens SQLite") |
| 128 | } |
| 129 | } |
| 130 | return true |
| 131 | }) |
| 132 | } |
| 133 | if !found { |
| 134 | t.Fatal("privileged caller does not cross the service registry boundary") |
| 135 | } |
| 136 | }) |
| 137 | } |
| 138 | } |
| 139 | |
| 140 | func TestStagedExecutableRegistryLookupCannotOpenSQLite(t *testing.T) { |
| 141 | entries, err := os.ReadDir("../instancectl") |
| 142 | if err != nil { |
| 143 | t.Fatal(err) |
| 144 | } |
| 145 | for _, entry := range entries { |
| 146 | if !strings.HasSuffix(entry.Name(), ".go") || strings.HasSuffix(entry.Name(), "_test.go") { |
| 147 | continue |
| 148 | } |
| 149 | f, err := parser.ParseFile(token.NewFileSet(), filepath.Join("../instancectl", entry.Name()), nil, parser.ImportsOnly) |
| 150 | if err != nil { |
| 151 | t.Fatal(err) |
| 152 | } |
| 153 | for _, imp := range f.Imports { |
| 154 | if imp.Path.Value == `"database/sql"` || strings.Contains(imp.Path.Value, "sqlite") { |
| 155 | t.Errorf("instancectl/%s imports SQLite instead of receiving the service registry view", entry.Name()) |
| 156 | } |
| 157 | } |
| 158 | } |
| 159 | } |
| 160 | |
amadan